cloudbase-init/cloudbaseinit/metadata/services/base.py

118 lines
2.8 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2012 Cloudbase Solutions Srl
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import abc
import time
from oslo.config import cfg
from cloudbaseinit.openstack.common import log as logging
opts = [
cfg.IntOpt('retry_count', default=5,
help='Max. number of attempts for fetching metadata in '
'case of transient errors'),
cfg.FloatOpt('retry_count_interval', default=4,
help='Interval between attempts in case of transient errors, '
'expressed in seconds'),
]
CONF = cfg.CONF
CONF.register_opts(opts)
LOG = logging.getLogger(__name__)
class NotExistingMetadataException(Exception):
pass
class BaseMetadataService(object):
def __init__(self):
self._cache = {}
self._enable_retry = False
def get_name(self):
return self.__class__.__name__
def load(self):
self._cache = {}
@abc.abstractmethod
def _get_data(self, path):
pass
def _exec_with_retry(self, action):
i = 0
while True:
try:
return action()
except NotExistingMetadataException:
raise
except Exception:
if self._enable_retry and i < CONF.retry_count:
i += 1
time.sleep(CONF.retry_count_interval)
else:
raise
def _get_cache_data(self, path):
if path in self._cache:
LOG.debug("Using cached copy of metadata: '%s'" % path)
return self._cache[path]
else:
data = self._exec_with_retry(lambda: self._get_data(path))
self._cache[path] = data
return data
def get_instance_id(self):
pass
def get_content(self, name):
pass
def get_user_data(self):
pass
def get_host_name(self):
pass
def get_public_keys(self):
pass
def get_network_config(self):
pass
def get_admin_password(self):
pass
@property
def can_post_password(self):
return False
@property
def is_password_set(self):
return False
def post_password(self, enc_password_b64):
pass
def get_client_auth_certs(self):
pass
def cleanup(self):
pass